Add X-Ray integration

[marcioAlmada]

Engine integration should come through a small php extension bridge instead:

https://github.com/marcioAlmada/xray

Reasons:

• hijacking the composer auto loader and passing things through a stream wrapper is not sustainable enough.
• using __halt_compiler as suggested in Real Time Mode #11 was a brilliant hack but it's a PITA for the end users.
• an engine extension can provide syntax check at preprocessor time effortlessly, even for global macros - aka not localized in the file being linted.

[chris-kruining]

Is an extension the only viable solution at this point? I ask because unlike packages there is no proper package manager for extensions. If I'm wrong, please tell me, such a manager would solve a lot of issues for me